This invention relates to panel assemblies especially adapted for use as windows in vehicles, buildings or other structures, as well as a method for manufacturing such panel assemblies.
Relatively recent in the history of vehicle panel assemblies, gaskets have been-molded or extruded directly onto the window panel. In molded window panels, a sheet of glass is closed within a molding tool and a polymeric material is then injected around the opposing surfaces of the peripheral edge thereby capturing the peripheral edge of the glass panel within the injected polymeric gasket. After the gasket is cured, the mold is opened and the panel assembly is removed. To retain the molded panel assembly within the vehicle, studs or clips may be molded within or attached to the gasket and used to engage the pinch weld flange forming the vehicle opening. Alternately, or in addition, a bead of adhesive is also often applied to bond the glass panel directly to the metal pinch flange. A bezel may be molded with the gasket to decorate and/or conceal space between the vehicle and the window assembly.
New styling requirements are calling for flush mounted glass panels having an exposed edge. One flush mounted vehicle panel assembly on the market includes extruded gaskets deposited directly on one surface of a glass sheet. Often the extrusion includes two adhesive beads of polyurethene compounds, one deposited by the panel assembly manufacturer and the other applied by the vehicle assembler. Disadvantages associated with extruded gaskets include long cure time for the first bead, adding cycle time to manufacturing, and constant cross-sectional profiles. In addition to being limited to uniform cross-sectional profiles, the gasket material used in forming extruded gaskets is typically not UV stable by itself and can degrade over time. Moreover, the extrusion does not easily adapt itself to receive mounting studs or clips. The extrusion compound is expensive and requires special storage and handling once formed and cannot be fully completed without creating a seam or gap in the gasket layout.
Another window assembly intended for use in flush mounted applications had a gasket molded directly to a single surface in a molding machine using reaction injection molded (RIM) urethane. Although this technique offered some variable cross sections, the presence of the glass and tooling limitations prevented or precluded gaskets having undercuts or lips. Other disadvantages include instability when subjected to prolonged exposures of ultraviolet light, long cycle times in forming, and increased material costs compared with other materials such as PVC. In addition, tensile or shear forces applied between the glass and gasket result in failure of the adhesive seal of the gasket with the panel as opposed to the desired loss of cohesion in the gasket itself.
None of the prior panel assemblies or methods are as versatile in providing flush mounted panel gaskets having unique cross-sectional profiles, with or without attaching or otherwise capturing fasteners. Moreover, none of the prior methods or panel assemblies can provide flush mounted panel gaskets having cross-sectional profiles which are variable along the panel assembly and satisfy complex sealing requirements.